Method of and means fob pbodttcino electbified jets of oas



R. H. GODDARD.

METHOD OF AND MEANS FOR PRODUCING ELECTRIFIED JETS 0F GAS.

APPLICATION men ocr. 4. 1911.

1,363,037. Patented Dec. 21, 1920.

UNITED STATES PATENT OFFICE.

ROBERT H. GODDARD, OF WORCESTER, MASSACHUSETTS.

METHOD OF AND MEANS FOR PRODUCING ELECTRIFIED JETQ GAS.

To all whom it may cmwem Be it known that I, Ronna'r H. Goonann, acitizen of the United States, residing at Worcester in the county ofWorcester and State of Massachusetts, have invented a new and usefulMethod of and Means for Producing Electrified Jets of Gas, of which thefollowing is a specification.

This invention relates to the production of an electrified jet of gas orvapor for any desired purpose such as the production of high potentials,and the principal object thereof is to provide for accomplishing thisresult in such a way that the electrified jet may be of substantiallyconstant character, independently of its velocity, and that change inthe velocity will not seriousl affect the result of the process; and, ins ort, to produce such a jet of gas in a highly efiicient manner.

According to this invention I introduce into the jet charged particlesor ions of one sign from a space not within the current of gas. In thisway no direct action of the current affects or modifies the introductionof the stream of charged particles. If a stream of air or other gas wereimpregnated with particles or ions by a means existing in the streamitself the effectiveness would be greatly limited. For example, if theions were produced by a hotfilament an increase in the velocity ofthegas would seriously cool the filament and if a discharge from pointswere employed, friction and eddies in the gas would increase rapidl withany increase of velocity. These ifliculties are done away with by myinvention, because if the ions or charged particles are produced in aspace through which the current does not pass they are out of the way ofthe direct action of the jet of gas and it may have any desired velocityor may contain any vapor or erosive solid particles and yet notinterfere with the production .of ions for introduction into the jet.Further objects and advantages of the invention will appear hereinafter.

Reference is to behad to the accompanyin drawings, in which Figure 1 isa sectional view of a form of apparatus for carrying out this invention;

Fig. 2 is a similar view of a modified-apparatus for charging the gas,and

Fig. 3 is a view of a complete modified apparatus, diagrammatic in form,and showing a modified utilizing apparatus in section.

Specification of Letters Patent.

Application filed October 4, 1917. Serial No. 194,785.

In the form of the apparatus shown in Big. 1 a high velocity air blastis forced through a main tube T. The ions are supplied to the jet by acomparatively low- VBIOCHLY blast in a side tube T the ions beingproduced by a hot platinum filament F, connected by wires'W and W to anysuitable source of current, such as a storage battery, or the secondaryof a small transformer. The current in the filament should be such as toheat it to incandescence while the air is flowing. The filament mayconsist of a fine platinum wire covered with oxids of the alkalineearths, or of porcelain, as in the N ernst glower, or of any othersubstance which may be readily rendered incandescent in the gas passingthrough the tube T The ions are caused to pass from the filament intothe stream of air in the tube T while passing through a metal cylinderC. This is connected by a wire W to a positive source of potential; somepoint of the heating system as P being connected to a negative source ofpotential. Experiments show, however, that an alternating source ofpotential' will work equally well at an air pressure. With even amoderate velocity of a1r in the tube T practically no ions will pass tothe cylinder C. The position of the cylinder or anode C in Fig. 1 andcorresponding parts in the other figures is such that a strong field isproduced which, if the jet of gas is absent, draws the ions from thefilament to the cylinder. However, when a jet of gas is maintained theions are found to be swept awa in the jet before they reach the anode Inshort, the cylinder 0 serves to draw the negative ions from thefilament, ,butthe jeuof gas sweeps the ions away before they can reachthe cylinder or anode. .1

This apparatus is preferably constructed from glass tubing, the wires Wand W, being protected by small, thin, glass tubes, one of them beingsupported by a piece of insulating material S. A high velocity can beused in the tube T without cooling the filament F, for the reason thatthe filament F is not in the tube T through which the high velocity jetto be electrified passes, but is in the side tube T in which there isonly a moderate speed of flow of gas; just sufiicient to carry the ionsproduced in the tube T into the main jet in the tube T. Further, aspray, as of water or mercury, may be present in the jet in the tube T,or even solid particles, without interfering in any way with theproduction of the ions in the tube T,. It is to be understood, ofcourse, that the method is not restricted to the supplying of negativeelectricity to the stream of gas in the tube T, because the filament canbe heated to such a temperature as to be charged positively and thecylinder C can then be charged negatively. Such positive currents will,however, usually be small.

Briefly, then the method involves the introduction of ions or chargedparticles of a given sign into a stream of gas, said ions being producedin a space adjacent to, but out of the direct path of, said stream.

Having thus described the method of and means for producing theelectrified jet, attention is called to certain applications of the jetso produced. There are various applications, depending upon how the jetcontaining the electric charges is changed or modified. For example, theions may be filtered from the stream of charged gas, much as dust isfiltered from air on passing through cotton wool. In this case animportant practical result is obtained, as hereinafter explained inconnection with the form shown in Fig. 1. Again, the jet of charged gasmay be made to issue from a metallic casing or envelop which containsall the apparatus necessary for producing the charged 'et, the chargesnot being filtered nor wit drawn from the jet. In this case other andentirel different useful results can be obtaine as hereinafter explainedin connection with the form shown in Fig. 3.

In particular, regarding the first application, such a jet can be usedas the essential part of an electrostatic machine. For exam le, if froma storage battery 110 volts di erence of potential is applied between a0.2 millimeter platinum filament, 15 millimeters long, and the brasscylinder C 3 millimeters in diameter, and a blast of air is forcedthrough the tube T under 10 lbs. pressure, and this is passed into ametallic receiver in which the ions are caught, a potential of thousandsof volls wi ll be roduced in the receiver. Also, as long as e blastcontinues, a small current can be taken from this high potentialreceiver. Such a receiver is shown in Fig. 1. The'blast is shown asentering tangentially, and slightl. obliquely, through an inlet from thetube into a cylindrical receptacle or can H, one end of which is closed.The air in the can passes out helically toward the open end through alarge plug of silvered glass-wool G, held in place by disks of wiregauze J--J. In this way most of the charged ions are continuallyfiltered from the air, producing a high potential in a manner analogousto the high hydrostatic pressure produced in a hydraulic ram, on thestopping of the flow of Water. The passage of the airitself is impededbut little. Sharp corners of the re ceiver are covered with Wax or otherinsulating substance K to prevent leakage of the charge. The currentavailable from the receiver is small, exceeding a milliampere, for theabove specifications, only when the space in which the ions are producedis a fairly good vacuum. Nevertheless, such currents are useful for anypurpose where a small current at high potential may be employed, as forexample in the operation of X-ray and other vacuum tubes.

A modification is shown in Fig. 2 in which the blast passes through thetube t, the metallic cylinder or anode 0 being located at the mouththereof with the leading-in wire 10,. The filament is in the form of acoil of platinum, or piece of foil 1, stationed near the open end of asmaller tube t, and connected with leadingin wires w, and "w In this wayit is not necessary to have a cur rent of air passing through the innertube t,, which is inclosed entirely within the larger tube. It ispossible to use a sharp metallic point for the filament lying along theaxis of the tube in place of the foil, but the foil is preferred as theions can be produced with lower potentials.

In Fig. 3 the invention is shown in a form in which the blast entersthrough a tube T and spreads out as shown by the dotted lines D. In acomparatively quiet region outside these dotted lines is placed thefilament F and the anode consisting of a metallic plate p. The dischargetends to pass through, and is carried away by, the blast. This method isoperative at any pressure, but when used for an electrostatic machine,pressure about the receiver should be about atmospheric or higher, orextremely low; for with a moderate vacuum the charge on the receiverleaks away rapidly. For example, under low pressures a blast of mercuryshould be used for the jet, practically a mercury difl'usion pump. Inthis case, the jet does not come in direct contact either with thefilament or the anode. The form shown in Fig. 3 is also well adapted fora purpose entirely different from the production of small currents (athigh potentials. This second application depends upon the fact that likecharges repel each other. Thus, if the 'et issues from a conductor whichis kept c arged to a high potential of the same sign as the charges inthe jet, by any well known means, then these latter charges will bestrongly repelled. Hence the velocity of the issuing jet Will beincreased, inasmuch as the charged particles will push along with themthe gas in which they are contained. All the metallic arts of the aparatus shown in Fig. 3 are inclosed in a su stantially spherical chargedconductor M which is kept at a very high potential. The sign of the chare on the conductor M is the same as that o the ions in the jet. Thepotential battery is indicated at B, and the filament battery at B Thespeed of the issuing jet is limited only b the power of the apparatus,which keeps Ni charged, to supply electrical energy and thus maintainthe potential, which would otherwise fall owing to loss of charge in thejet.

The production of extremely high potentials, in this way, is ofimportance in, for example, jet propulsion. I have shown and describedin my United States Patent No. 1,102,653, propulsion by gaseous jetsproduced by chemical means, in which velocities were attained doublethose produced by steam turbine nozzles. These velocities are thegreatest that have yet been produced in any way with masses of gas ofappreciably large magnitude, but are much less than are possible by themethod herein described, for the reason that the potential of thecontainer M, which produces the high velocity, may be as high asdesired.

Attention is called to the fact that the high potential, in this case,is produced by some external means and does not result in any way fromthe electrified jet. It is to be understood that the two applicationsshown are only illustrated and that the several forms of producingapparatus are not limited to the applications herein shown in connectionwith them.

It should further be understood that these applications involve the useof a high velocity jet of electrically charged gas; and that such a jetcan be produced effectively only by the means herein described, wherebythe ions are produced in a space outside of but adjacent to the directaction of the jet.

Although I have shown and described only three forms of the invention Iam aware or" the fact that other modifications can be made therein byany person skilled in the art without departing from the scope'of theinvention as expressed in the claims. Therefore I do not wish to belimited to all the details of construction or the specific combinationsherein shown and described, but what I do claim is 1 The method ofproducing an electrified jet of gas which. consists in conducting acurrent of gas along a course,'producing a stream of charged particlesindependently thereof, and introducing the same into the jet to beelectrified, thus preventing the jet from previously influencing thecharged stream.

2. A method of electrifying a jet of gas which consists in conducting acurrent of gas along a course, and producing ions adjacent to, but outof contact with, the current of gas, and directing the ions into thecurrent, whereby the current will take them up substantially at theirsource and be charged by them.

3. The method of producing and utilizing an electrified jet of gas whichconsists in introducing charged particles of one sign from an externalsource into a jet of gas, causing said gas to pass along in a helicalcourse and removing the electrified particles from the gas.

4. The method of producing an electrified jet of gas which consists inintroducing a stream of charged particles into the jet from a spacethrough which the jet does not pass, and subjecting the jet to theinfluence of electricity of the same sign as that of the ions in thejet.

5. In an apparatus of the class described, the combination of a tubeadapted to conduct a gas, a tube outside said tube separated therefromexcept at one point near the point of production of the jet, a filamentlocated at said point and constituting part of an electric circuit, anda charged tube within the last named tube connected with a source ofpotential.

6. In an apparatus of the character described, the combination of a tubefor conducting a jet of gas, and means located out of contact with thegas passing through said tube for producing ions and directing a streamof them into the jet.

7. In an apparatus of the character described, the combination of a tubefor con ducting a stream of gas, with an auxiliary tube leading intosaid tube at a point near the mouth thereof and adapted to conduct acurrent thereto, a filament in said auxiliary tube heated by a source ofelectricity, and a metallic member connected to a positive source ofpotential, a point connected with the filament also being connected withthe negative pole of the same source of potential, whereby chargedparticles will be produced and introduced into the jet.

8. In an apparatus of the character described, the combination of a tubefor conducting a jet of gas, means located out of contact with the gaspassing through said tube for producing ions at a point from which theywill be introduced into the jet, and means for directing said jet in asinuous course to conduct the charged particles from it,

9. In an apparatus of the character described, the combination of a tubefor conducting a jet of gas, and means located out of contact with thegas passing through said tube for producing 10118 in a stream andintroducing the stream into the jet, with a charged metallic conductorinclosing the stream of ions.

In testimony whereof I have hereunto affixed my signature.

ROBERT H. GODDARD,

